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Abstract:

The container has a tubular body having a peripheral lateral wall
provided with an upper end portion and a lower end portion defining an
upper retention hook and a lower retention hook to which is double-seamed
a lower end wall. An upper end wall is conformed to incorporate a
peripheral upper skirt presenting an end edge defining an inverted U
shaped upper closure hook to be seated onto the upper retention hook
sandwiching an elastic sealing element therebetween. The upper closure
hook and the upper retention hook and also a portion of the peripheral
upper skirt and a confronting region of the upper end portion are
deformed for seaming the upper closure hook onto the upper retention hook
and to form, respectively, a retention rib and a retention groove which
tightly fits the retention rib.

Claims:

1. A process for closing a container in metal sheet, of the type which
comprises a tubular body formed by a peripheral lateral wall having an
upper end portion and a lower end portion, to which an upper end wall and
a lower end wall are respectively affixed, characterized in that it
comprises the steps of: conforming a metal sheet portion to define the
peripheral lateral wall of the tubular body; conforming the peripheral
lateral wall so as to provide, in its upper end portion, an upper
peripheral edge which is outwardly and downwardly bent, defining an upper
retention hook with a profile in the form of an inverted U; and, in its
lower end portion, a lower peripheral edge which is bent to define a
lower retention hook; peripherally affixing the lower end wall to the
lower retention hook of the tubular body; conforming a metal sheet
portion to define an upper end wall having a median panel and a
peripheral upper skirt which presents an end edge which is outwardly,
downwardly and inwardly bent, so as to define an upper closure hook with
a profile in the form of an inverted U; fitting and seating the
peripheral upper skirt in the interior of the upper end portion, with the
container being empty or already filled with the product, so as to seat
the upper closure hook onto the upper retention hook sandwiching an
elastic sealing element previously provided between said hooks; and
submitting the upper closure hook and the upper retention hook and also a
portion of the peripheral upper skirt and a confronting region of the
upper end portion to a simultaneous deformation operation, in order to
seam the upper closure hook onto the upper retention hook, compressing
the elastic sealing element, and to form at least one outer
circumferential retention rib in the peripheral upper skirt and a
corresponding inner circumferential retention groove in the upper end
portion of the peripheral lateral wall, tightly fitting the retention
rib.

2. The process, as set forth in claim 1, characterized in that the upper
retention hook, with the profile in the form of an inverted U, is
conformed to present an inner lateral leg defined by part of the upper
end portion, an arched base leg and an outer lateral leg which is
convergent in relation to the inner lateral leg, the upper closure hook,
with the profile in the form of an inverted U, being conformed to present
an inner lateral portion defined by an upper part of the peripheral upper
skirt, an arched base portion and an outer lateral portion which is
convergent in relation to the inner lateral portion and internally
incorporating an upwardly projecting end flange the fitting of the upper
closure hook onto the upper retention hook being made so that the arched
base portion of the former is seated onto the arched base leg of the
latter, with the elastic sealing element being disposed between said
arched base portion and arched base leg, and the seaming of the upper
closure hook onto the upper retention hook being made so as to seat the
inner lateral portion, the arched base portion and the outer lateral
portion of the upper closure hook respectively against the inner lateral
leg, the arched base leg and outer lateral leg of the upper retention
hook, compressing the elastic sealing element and having the end flange
projecting upwardly to the interior of the upper retention hook, between
the outer lateral leg and the inner lateral leg of the latter.

3. The process, as set forth in claim 2, characterized in that the
deformation of the upper closure hook and upper retention hook is
obtained by applying an inward upward radial force, in opposition to the
application of an outward radial force against the peripheral upper skirt
and the upper end portion of the peripheral lateral wall, in order to
simultaneously form the retention rib and the retention groove.

4. The process, as set forth in claim 2, characterized in that the outer
lateral leg and the outer lateral portion of the upper retention hook and
of the upper closure hook respectively, are substantially rectilinear and
inclined downwardly and radially inwardly.

5. The process, as set forth in claim 2, characterized in that the inner
lateral leg and the inner lateral portion of the upper retention hook and
of the upper closure hook, respectively, are substantially rectilinear
and slightly inclined upwardly and radially outwardly.

6. The process, as set forth in claim 2, characterized in that the
elastic sealing element has a portion of its extension penetrating and
being compressed between the inner lateral leg and the inner lateral
portion of the upper retention hook and the upper closure hook,
respectively.

7. The process, as set forth in claim 2, characterized in that the
retention rib and the retention groove are formed by deforming the metal
sheet of the respective parts and present a cross section with the
approximate form of a rounded V, in a convex arc and a concave arc,
respectively.

Description:

FIELD OF THE INVENTION

[0001] The present invention refers to a process to provide the upper
closure of a container formed in metal sheet, such as a closed pail or
other container comprising a peripheral lateral wall, with a cylindrical
form or an inverted and slightly frusto-conical form and presenting an
upper end portion and a lower end portion, to which respective end walls
are attached.

PRIOR ART

[0002] The containers of the type considered herein have their upper and
lower end walls respectively and peripherally double-seamed in the upper
end portion and lower end portion of the peripheral lateral wall, the
upper end wall being provided with an a generally eccentric opening
having a contour substantially smaller than that of the peripheral
lateral wall, and with a gripping handle contained in the interior of the
axial projection of the contour of the container, in order to allow the
latter to be lifted by the gripping handle attached only to the upper end
wall. The opening provided on the upper end wall is configured to define
a seat to which is applied a lid generally formed in a plastic material.

[0003] Due to the complexity of the double-seaming processes, which
require the use of specific and generally expensive equipment, these
double-seaming phases in the manufacture of the container considered
herein are rarely carried out in the product filling facilities. Thus,
the containers are closed in the manufacturer's facilities, by
double-seaming the end walls to the peripheral lateral wall of the
container, being then shipped to the facilities for filling the product
to be commercialized. Since the containers are shipped with the end walls
already double-seamed to the peripheral lateral wall, they cannot be
fitted one inside the other, requiring to be arranged side-by-side and
stacked in the transport vehicles and also in the storage places, both at
the container manufacturer and at the filling facilities, requiring a
physical space presenting an undesirable large volume in relation to the
mass of the material, considerably increasing the shipping and storage
costs and requiring special cares to transport these containers.

[0004] Another drawback of these containers supplied to the responsible
for the filling operation with the end walls already attached, generally
by double-seaming, results from the fact that the filling can be only
carried out through the opening of reduced dimension provided in the
upper end wall. Thus, the time for filling the product is longer than
that corresponding to the filling carried out without the upper end wall,
as it occurs upon filling containers which are superiorly closed by a
removable lid and provided with a suspension handle applied to the
peripheral lateral wall and not to the lid.

[0005] Aiming to overcome the inconveniences cited above, it was proposed
a constructive solution object of the Brazilian patent application PI
0804305-1, "CONTAINER IN METAL SHEET", filed on Oct. 9, 2008 by the
present applicant. In this prior solution, the upper end wall can be
easily, quickly, reliably and hermetically affixed to the peripheral
lateral wall of the container by the filler of the product, without
requiring double-seaming operations.

[0006] According to said prior constructive solution of the same
applicant, the upper peripheral edge of the peripheral lateral wall and
the outer peripheral edge of the upper wall are conformed to allow them,
through a simple and simultaneous deformation operation to be carried out
by the filler, to be reliably and hermetically affixed to each other,
generally with the aid of an elastic sealing element, in the form of a
gasket compressed between the deformed edges of the peripheral lateral
wall and the upper wall.

[0007] In the applications in which a high degree of axial retention is
required between the upper wall, provided with a suspension handle, and
the peripheral lateral wall of the container, the upper end portion of
the latter and the peripheral upper skirt of the upper end wall are
provided with one or more circumferential ribs and grooves which
cooperate with each other, upon fitting the upper end wall in the
interior of the upper end portion of the peripheral lateral wall.

[0008] Although the provision of the circumferential ribs and grooves
leads to a substantial increase in the degree of axial retention of the
upper end wall, as well as in the degree of hermeticity in said upper
closure of the container, these ribs and grooves are provided separately
in the skirt of the upper end wall and in the peripheral lateral wall of
the container, by the manufacturer of the latter, requiring an
undesirable dimensional precision in the manufacture of the two parts, in
order to allow fitting them at the final closure of the container and
obtaining the desired degrees of axial retention and additional sealing.
This prior solution, although providing the advantages mentioned in said
prior patent application of the same applicant, has the inconvenience of
requiring costly manufacturing procedures.

SUMMARY OF THE INVENTION

[0009] Due to the inconvenience commented above in relation to the prior
solution, it is an object of the present invention to provide a process
for closing a container in metal sheet, having a peripheral lateral wall,
a lower end wall and an upper end wall which is provided with a small
discharge opening and with a suspension handle and which can be easily,
quickly, reliably and hermetically affixed to the peripheral lateral wall
by the filler of the product to be packaged, without requiring
double-seaming operations or costly operations for conforming the
peripheral lateral wall and the upper end wall with reduced dimensional
tolerances.

[0010] The present process is applied for closing a container in metal
sheet, of the type which comprises a tubular body formed by a peripheral
lateral wall having an upper end portion and a lower end portion, to
which respective upper and lower end walls are attached.

[0011] According to the invention, the closing process comprises the steps
of forming the tubular body in metal sheet, conforming its upper and
lower end portions, so as to provide them, respectively, with an upper
retention hook and with a lower retention hook, the lower retention hook
being conventionally double-seamed to the lower end wall.

[0012] The upper end wall is conformed in metal sheet, so as to present a
peripheral upper skirt with its end edge being bent to configure an upper
closure hook when the container is superiorly closed, still empty or
already filled with the product.

[0013] The upper closure hook and the upper retention hook and also the
peripheral upper skirt of the upper end wall and the upper end portion of
the peripheral lateral wall are then deformed together, in order to
provide a seaming of said hooks, upon compressing an intermediary elastic
sealing element, and also the formation of at least one outer
circumferential retention rib in the peripheral upper skirt and a
respective inner circumferential retention groove in the upper end
portion of the peripheral lateral wall, tightly fitting the retention
rib.

[0014] The closing process proposed by the invention allows the upper end
wall to be hermetically and reliably seamed to the tubular body of the
container, without requiring the costly and complex operations of
double-seaming or previously forming the retention ribs and grooves with
expensive dimensional tolerances which hamper the manufacture and raise
the costs of these containers.

[0015] With the proposed process, the containers can be manufactured
without the retention ribs and grooves and conveyed to be filled, with
the upper end wall still as a separate piece, but with the lower end wall
already duly double-seamed to the tubular body.

[0016] In the proposed solution, the whole cross section of the still open
upper end portion can be used during the filling, reducing the operation
time before the operation of fitting and retaining the respective end
wall in the interior of the peripheral lateral wall, by means of simple
and concomitant axial and radial compression operations, to provide the
deformation of both the closure hook and the upper retention hook and the
concomitant formation of the circumferential rib and groove.

[0017] In case the peripheral lateral wall is constructed so as to taper
from one end portion to the other, generally from the upper end portion
to the lower end portion, in a continuous or stepped manner, the
containers can be stored and shipped without the upper end wall and in a
condition in which they remain partially fitted one inside the other in
stacks, allowing a substantial economy in storage and transportation
volume until they are closed at the filling facility and, preferably,
after the filling operation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will be described below, with reference to the
enclosed drawings, given by way of example of one of the possible
embodiments of the invention and in which:

[0019]FIG. 1 represents a top plan view of the present container, with
its peripheral lateral wall presenting a circular contour;

[0020]FIG. 2 represents a partial diametrical sectional view of the
container, illustrating the upper end wall and lower end wall affixed to
the peripheral lateral wall, said section taken according to line II-II
in FIG. 1;

[0021]FIG. 3 represents an enlarged exploded detail of the region of FIG.
2 which illustrates the fitting of the upper end wall in the upper end
portion of the peripheral lateral wall, illustrating the form of the
component parts before seating the upper end wall onto the peripheral
lateral wall;

[0022]FIG. 4 represents the same detail of FIG. 3, but illustrating the
upper end wall already seated and only provisionally retained to the
peripheral lateral wall;

[0023]FIG. 5 represents a reduced lateral view of the container
represented in FIG. 4 when a seaming device is applied thereto for
compressing the closure hook and the upper retention hook, for forming
the axial retention rib and groove.

[0024]FIG. 5A represents a view similar to that of FIG. 4, but
illustrating the application of the seaming device to provide the
simultaneous deformation of the closure hook and upper retention hook and
of the peripheral upper skirt together with the upper end portion of the
peripheral lateral wall, so as to form the circumferential rib and groove
to be tightly fitted together;

[0025] FIG. 6 represents a view similar to that of FIG. 5, but
illustrating only the container; and

[0026]FIG. 7 represents a partial diametrical sectional view of two
containers constructed according to the present process, deprived of the
upper end wall and partially fitted one into the other.

DESCRIPTION OF THE INVENTION

[0027] The present closing process is applied to a container formed in
metal sheet, usually tinplate, and comprising a tubular body C formed by
a peripheral lateral wall 10, with any polygonal cross section, usually
circular and having an upper end portion 10a and a lower end portion 10b,
in which respective upper end wall 20 and lower end wall 30 are affixed.

[0028] According to the invention, after conforming a metal sheet portion
to form the tubular body C, the latter is submitted to an operation for
conforming the upper end portion 10a and lower end portion 10b of the
peripheral lateral wall 10.

[0029] The conformation of the upper end portion 10a is made so as to
provide, therein, an upper peripheral edge 10c which is outwardly and
downwardly bent, defining an upper retention hook 11 with a profile in
the spa approximate form of an inverted U.

[0030] In the preferred form of the invention, the upper retention hook 11
is conformed to present an inner lateral leg 11a defined by part of the
upper end portion 10a of the peripheral lateral wall 10, an arched base
leg 11b and an outer lateral leg 11c which is convergent in relation to
the inner lateral leg 11a. The conformation of the lower end portion 10b
of the peripheral lateral wall 10 is made to provide a lower peripheral
edge 10d which is outwardly bent to define a lower retention hook 12
which may present any known prior art configuration to allow the
fixation, for example by double-seaming, of the likewise conformed
peripheral edge of the lower end wall 30, also in metal sheet and with
any conventional construction. The solution used to reliably and
hermetically affix the lower end wall 30 to the tubular body C is not a
particular aspect of the present process, which fixation may be carried
out at the manufacturer's facilities by any adequate method.

[0031] After conforming the tubular body C and the upper retention hook 11
and the lower retention hook 12, a peripheral edge of the lower end wall
30 is affixed to the tubular body C, generally by double-seaming.

[0032] Concomitantly to the formation of the tubular body C and to the
closing of its lower end wall 30, a metal sheet portion is conformed to
define the upper end wall comprising a median panel 21, which is
optionally provided with well known prior art stiffening circumferential
ridges, and with a peripheral upper skirt 22, projecting axially
outwardly and which is configured to be tightly fitted, under
interference, in the interior of the upper end portion 10a of the
peripheral lateral wall 10.

[0033] The peripheral upper skirt 22 has an end edge 22c which is,
outwardly, downwardly and inwardly bent, so as to define a closure hook
23 with a profile in the approximate form of an inverted U.

[0034] In the preferred and illustrated form, the closure hook 23 is
conformed to present an inner lateral portion 23a, defined by an upper
part of the peripheral upper skirt 22 of the upper end wall 20, an arched
base portion 23b and an outer lateral portion 23c which is convergent in
relation to the inner lateral portion 23a and which internally
incorporates an end flange 23d which projects upwardly.

[0035] According to the process of the invention, the peripheral upper
skirt 22 of the upper end wall 20 can be then fitted and seated in the
interior of the upper end portion 10a of the peripheral lateral wall 10,
with the container being empty or already filled with the product, said
fitting being carried out to seat the closure hook 23 onto the upper
retention hook 11, sandwiching an elastic sealing element 40 previously
provided between said hooks 23, 11. (See FIGS. 4, 5A and 6).

[0036] In the solution illustrated in the drawings, the fitting of the
closure hook 23 onto the upper retention hook 11 is made so that the
arched base portion 23b of the former is seated on the arched base leg
11b of the latter, with the elastic sealing element 40, for example a
plastisol film, being disposed between said arched base portion 23b and
arched base leg 11b.

[0037] As illustrated, the elastic sealing element 40 is preferably
applied under the arched base portion 23b of the closure hook 23, so as
to be seated against the arched base leg 11b of the upper retention hook
11 upon fitting and seating the upper end wall 20 in the interior of the
upper end portion 10a of the peripheral lateral wall 10.

[0038] The exploded view of FIG. 3 illustrates the form imparted to the
parts before closing the container. In this stage, the diameter of the
free end edge of the outer lateral leg 11c of the upper retention hook 11
is slightly smaller than the diameter of the free upper edge of the end
flange 23d which projects upwardly outwardly inclined. Thus, upon seating
the upper end wall 20 in the condition illustrated in FIG. 4, both said
parts suffer an elastic deformation to allow the end flange 23d to be
fitted under the free end edge of the outer lateral leg 11c of the upper
retention hook 11.

[0039] Being the container ready to be closed, generally after having
already been filled with the product to be packaged, with the upper end
wall 20 being already fitted and seated in the interior of the upper end
portion 10a of the peripheral lateral wall 10, the closure hook 23 and
the upper retention hook 11 and also a portion of the peripheral upper
skirt 22 and a confronting region of the upper end portion 10a may be
submitted to a joint deformation operation, so as to provide the seaming
of the closure hook 23 onto the upper retention hook 11, compressing the
elastic sealing element 40 therebetween and further forming at least one
outer circumferential retention rib 24 in the peripheral upper skirt 22
and one inner circumferential retention groove 14 in the upper end
portion 10a of the peripheral lateral wall 10, said retention rib 24
being tightly fitted in the interior of the retention groove 14,
guaranteeing a tight and reliable coupling between the parts of tubular
body C and upper end wall 20, without requiring especial manufacturing
cares for allowing the retention rib 24 to perfectly follow the inner
contour of the retention groove 14.

[0040] The deformation of both the closure hook 23 and the upper retention
hook 11 is obtained by applying an inward and upward radial force, in
opposition to the application of an outward radial force, against the
peripheral upper skirt 22 and the upper end portion 10a of the peripheral
lateral wall 10, in order to simultaneously form the retention rib 24 and
the retention groove 14.

[0041] In the preferred and illustrated construction, the fitting of the
closure hook 23 onto the upper retention hook 11 is made so that the
arched base portion 23b of the closure hook 23 is seated onto the arched
base leg 11b of the upper retention hook 11, the seaming of the closure
hook 23 onto the upper retention hook 11 also being made so as to seat
the inner lateral portion 23a, arched base portion 23b and outer lateral
portion 23c of the closure hook 23 respectively against the inner lateral
leg 11a, arched base leg 11b and outer lateral leg 11c of the upper
retention hook 11, compressing the elastic sealing element 40 and having
the end flange 23d projecting upwardly to the interior of the upper
retention hook 11, between the outer lateral leg 11b and the inner
lateral leg 11a of the latter.

[0042] As illustrated in FIGS. 5 and 5A, the deformations for seaming the
hooks and for forming the retention rib 24 and the retention groove 14
can be easily carried out after the filling of the product, by means of a
seaming device 50 which comprises a plurality of outer peripheral fingers
51 and a plurality of inner peripheral fingers 52, said outer peripheral
fingers 51 and inner peripheral fingers 52 being configured to jointly
define circular alignments, with a variable diameter as a function of the
operation of the seaming device 50, and to act simultaneously against the
hooks from the outer side of the container and against the peripheral
upper skirt 22, so as to simultaneously produce the seaming deformation
of both the upper closure hook 23 and the upper retention hook 11 and the
formation of both the retention rib 24 and the retention groove 14. As
can be noted in FIG. 5A, the outer peripheral fingers 51 and inner
peripheral fingers 52 are configured to impart, to the respective parts
against which they are seated, the desired conformation to obtain both
the seaming of the hooks and the fitting between the peripheral upper
skirt 22 and the upper end portion 10a of the peripheral lateral wall 10,
guaranteeing a strong axial retention between the upper end wall 20 and
the tubular body C of the container, besides establishing a sealing
region additionally to that defined by the seaming of the closure hook 23
and upper retention hook 11, with the provision of the elastic sealing
element 40 therebetween.

[0043] Further as illustrated, after finishing the deformation of the
closure hook 23 and upper retention hook 11, the outer lateral leg 11c of
the upper retention hook 11 and the outer lateral portion 23c of the
closure hook assume a substantially rectilinear and downwardly and
radially inwardly inclined profile, guaranteeing a strong, reliable and
tight fixation of the upper end wall 20 to the peripheral lateral wall
10.

[0044] With the purpose of facilitating the accommodation of the two parts
to be fixed to each other, as well as the operations of plastic
deformation of the metal sheet upon the initial and final formation of
the two hooks, the inner lateral leg 11a of the upper retention hook 11
and the inner lateral portion 23a of the closure hook 23 are initially
conformed to present a profile that is substantially rectilinear and
slightly inclined upwardly and radially outwardly.

[0045] According to the illustrated embodiment, the retention rib 24 and
the retention groove 14 are constructed so as to present a cross section
with the approximate form of a rounded V, in a convex and in a concave
arc, respectively.

[0046] Depending on the characteristics of the application of the elastic
sealing element 40, it may have a portion of its extension penetrating
and being compressed between the inner lateral leg 11a and the inner
lateral portion 23a of the upper retention hook 11 and of the closure
hook 23, respectively, as illustrated in FIG. 5.

[0047] Considering that the construction of the present container aims at
obtaining a closure which is easily executed, but which can comply with
the safety requirements applied to the containers for dangerous products,
the peripheral lateral wall can be provided with energy absorbing means
by controlled plastic deformation. Thus, the peripheral lateral wall 10
can present two regions respectively adjacent to the upper end portion
10a and lower end portion 10b, each occupying about 10% to 15% of the
height of the peripheral lateral wall 10 and conformed in a plurality of
circumferential grooves 10e presenting a profile in the form of a laid V
with a rounded apex. These regions present a pleated structure which
tends to deform before an undue deformation of the container occurs in
the regions in which the end walls 20, 30 are affixed to the peripheral
lateral wall 10.

[0048] As can be observed in FIGS. 1 and 2, considering that the two upper
end wall 20 and lower end wall 30 are affixed, in a non-removable manner,
to the peripheral lateral wall 10, the median panel 21 of the upper end
wall 20 is provided with a generally eccentric opening 21a of smaller
diameter, and with a gripping handle 60 generally positioned in the
central region of said upper end wall 20, the gripping handle 60 being
integrally affixed in said upper end wall 20, so as to allow the
container, even if filled, to be lifted by said gripping handle 60. In
this type of construction, the smaller diameter opening 21a is usually
closed by a removable lid; preferably constructed in a plastic material
and which is not illustrated herein, as it forms no part of the present
invention.

[0049] As already previously mentioned and further illustrated in FIG. 7
of the enclosed drawings, the peripheral lateral wall 10 of the container
can be constructed to allow the partial telescopic fitting between two
stacked containers. In the illustrated embodiment, the peripheral lateral
wall 10 has an inverted and slightly frusto-conical form, the smaller
base coinciding with the lower end wall 30 and the larger base being
preferably situated in a plane axially spaced back in relation to the
mounting plane of the upper end wall 20 and in which the peripheral
lateral wall 10 is deformed to define an outer circumferential projection
19.

[0050] With this construction, a container can be telescopically fitted
inside another inferiorly disposed container deprived of the upper end
wall, this fitting, as illustrated in FIG. 7, being carried out until the
outer circumferential projection 19 is seated onto the free edge of the
upper end portion 10a of the peripheral lateral wall 10 of the inferiorly
disposed container, allowing the thus stacked containers to occupy a
total volume substantially inferior to the volume that would be occupied
with the same number of inferiorly and superiorly closed containers
stacked one on top of the other. With this partial fitting arrangement,
the containers can be stored and shipped with a great economy in volume
and, accordingly, in cost.

[0051] While only one embodiment of the invention has been illustrated
herein, it should be understood that the present closing process can
suffer alterations in the deformation characteristics of the involved
parts, without departing from the constructive concept defined in the
claims that accompany the present specification.